From 590d8320992d74e54e2c095c68c49abc2b23dcbe Mon Sep 17 00:00:00 2001 From: Nicolas Lacasse Date: Fri, 7 Sep 2018 10:04:11 -0700 Subject: [PATCH] runsc: Dup debug log file to stderr, so sentry panics don't get lost. Docker and containerd do not expose runsc's stderr, so tracking down sentry panics can be painful. If we have a debug log file, we should send panics (and all stderr data) to the log file. PiperOrigin-RevId: 211992321 Change-Id: I5f0d2f45f35c110a38dab86bafc695aaba42f7a3 --- runsc/main.go | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/runsc/main.go b/runsc/main.go index 0c9b9af78..c51b199aa 100644 --- a/runsc/main.go +++ b/runsc/main.go @@ -179,6 +179,10 @@ func main() { if *debugLogFD > -1 { f := os.NewFile(uintptr(*debugLogFD), "debug log file") + // Dup f to stderr so we capture stack traces on panic. + if err := syscall.Dup2(int(f.Fd()), int(os.Stderr.Fd())); err != nil { + cmd.Fatalf("error dup'ing fd %d to stderr: %v", f.Fd(), err) + } e = log.MultiEmitter{e, log.GoogleEmitter{&log.Writer{Next: f}}} } else if *debugLogDir != "" { if err := os.MkdirAll(*debugLogDir, 0775); err != nil { @@ -189,6 +193,10 @@ func main() { if err != nil { cmd.Fatalf("error opening debug log file in %q: %v", *debugLogDir, err) } + // Dup f to stderr so we capture stack traces on panic. + if err := syscall.Dup2(int(f.Fd()), int(os.Stderr.Fd())); err != nil { + cmd.Fatalf("error dup'ing fd %d to stderr: %v", f.Fd(), err) + } e = log.MultiEmitter{e, log.GoogleEmitter{&log.Writer{Next: f}}} }